Micro-support structures

ABSTRACT

A MEM device in accordance with the invention comprises one or more movable micro-structures which are preferably ribbon structures or cantilever structures. The ribbon structures or cantilever structures are preferably coupled to a substrate structure through one or more support regions comprising a plurality of anchor support features and a plurality of post support features. The MEM device is preferably an optical MEM device with a plurality of movable ribbon structures each being supported by opposing ends through support regions each comprising a plurality of anchor support features and a plurality of post support features. In accordance with the method of the embodiments, the positions of the anchor and post support features, the number of anchor and support features and the spacings between the support features can selected during fabrication of the device to determine an operating condition of the MEM device.

FIELD OF THE INVENTION

The invention relates to support structures for micro-structures. Moreparticularly, the present invention relates to support structures formicro-structures in micro-electro mechanical machines.

BACKGROUND OF THE INVENTION

A number of micro-machines utilize movable cantilevers, ribbonstructures or other similar micro-structures. Typically, these-microstructures are extremely thin; on the order of hundreds or thousands ofAngstroms, and are formed through release etch processes. These thinmicro-structures can experience a high degree of stress and tension,either during fabrication and/or during operation of the device. Largermicro-structures can experience stress or tension on the order of 1.5GPa or higher. Micro-support structures can fail under such conditionsleading to device failure.

Optical MEM devices are used to modulate one or more wavelengths oflight. Optical MEM devices can have applications in display, print andelectrical device technologies. Examples of an optical MEM device whichutilize suspended micro-ribbon structures to modulate light aredisclosed in the U.S. Pat. Nos. 5,311,360, 5,841,579 and 5,808,797, allissued to Bloom et al., the contents of which are hereby incorporated byreference.

Briefly, an optical MEM device described in the above referenced patentshas one or more sets of movable ribbons that comprise a support layerand a reflective top-layer. The support layer is preferably a siliconnitride layer and the reflective top-layer is preferably an aluminumlayer. The ribbon structures are typically secured to a substratethrough opposite ends of the ribbon, whereby center portions of theribbons, referred to herein as the active portions, move up and down tomodulate an incident light source.

For particular applications, most notable in optical communications,larger ribbon structures are preferred. As previously mentioned, theselarger ribbon structures can be subject to high levels of stress andtension both in the fabrication of the device and during the operationof the device. Accordingly, there is a desire for MEM devices withmechanical support structures which are capable of supportingmicro-structures exhibiting high stress and/or tension. Further, what isdesirable is a method for controlling or tunning the resonant frequencyor frequencies and/or the operating voltage or voltages required todeflect the active portions of ribbon structures in an optical MEMstructure.

SUMMARY OF THE INVENTION

The current invention is directed to a micro-device comprising at leastone suspended micro-structure which is preferably a ribbon structure orcantilever structure. The micro-structure is coupled to a substratestructure by at least one end through a securing region. The securingregion preferably comprises sets of securing features arranged along theattached end of the suspended micro-structure. The sets of securingfeatures comprises a plurality of anchor support features and aplurality of post support features. The anchor support features and thepost support features are preferably arranged in parallel and laterallyalong the attached end of the micro-structure.

A micro-device in accordance with the embodiments preferably comprises aplurality of ribbon structures configured to modulate light having awavelength in a range of approximately 300 to 3000 nanometers. Ribbonstructures in accordance with the embodiments can be formed to havelengths in a range of 50 to 1000 microns and widths in a range of 4.0 to40 microns, wherein the stress and/or tension of the ribbon structurescan be as great as 1.5 Gpa or higher.

The ribbon structures are preferably coupled through securing regionspositioned at opposite ends of each of the ribbon structures. Each ofthe supporting regions preferably comprises a plurality of anchorsupport features and a plurality of post support features arranged inparallel rows along the ends of adjacent ribbon structures. However,embodiments with anchor support features and post support features thatare arranged in a staggered fashion and/or with alternating separationsbetween anchor support features and post support features on adjacentribbons structures are contemplated.

In accordance with the embodiments a micro-structure comprises a devicelayer that preferably comprises a silicon nitride layer with a thicknessin a range of 200 to 2000 Angstroms. The device layer can also comprisea top-layer of aluminum with a thickness in a range 250 to 1000Angstroms thick. The device layer, in accordance with the embodimentscan also comprise one or more silicon dioxide layers, either under thenitride layer or between the nitride and the aluminum top layer, asdescribed in detail below.

In accordance with a preferred method of the embodiments, a sacrificiallayer, which can be a poly-silicon layer, is deposited to a thickness ina range of 0.5 to 3.0 micron on a suitable substrate structure. Thesubstrate structure can include one or more barrier oxide layers, asdescribed in detail below. The sacrificial layer is then patterned,preferably through an etch process, with at least one set of anchor andpost trenches or dimples. The anchor trenches, or dimples, arepreferably etched to have cross-sectional dimensions in a range of 5.0to 20 microns, while the post trenches, or dimples, are preferablyetched to have cross-sectional dimensions in a range of 0.5 to 5.0microns. A device layer, preferably comprising an etch resistantmaterial, is then deposited over the patterned sacrificial layer andwithin the etched tenches, or dimples, such that portions of the devicelayer couple to the substrate structure therebelow through the trenches,or dimples, to form the anchor and post support features. The deviceslayer preferably comprises a silicon nitride-based layer that isdeposited to a thickness in a range of 500 to 2000 Angstroms and morepreferably deposited to a thickness in a range of 700 to 1200 Angstroms.The device layer can also include one or more silicon oxide-based layersformed over and/or under the silicon nitride-based layer deposited tothicknesses in a range of 500 to 2000 Angstroms.

After the device layer is formed, then the device layer is preferablycut, or divided, into ribbon structures. The device layer can be cutinto ribbon structures using a reactive ion etch or other suitableprocess. The ribbon structures are preferably arranged in parallel withthe dimensions such as those described above. The device layer ispreferably cut such that two or more anchor and two or more post supportfeatures couple each end of the ribbon structures to the substratestructure. The separations between adjacent ribbon structures ispreferably as small as possible, and can be on the order of 0.5 micronsor less. After the device layer is divided or cut into ribbonstructures, then the sacrificial layer is etched to release the ribbonfeatures with the ribbon features suspended over the substrate structureand coupled to the substrate structure through the anchor and postsupport features formed therefrom.

The separations between the anchor and post supporting features can betailored to achieve physical properties of the ribbon structuressuitable for the application at hand. Each of the ribbon structurespreferably has multiple exterior anchor support features and multipleinterior post support features arranged near each end of the ribbonstructures. Using multiple anchor support features and post supportfeatures allows the ribbon structures to be readily tuned or tailoredfor an operating frequency or set of frequencies and a switching voltageor set of switching voltages and also provides a larger effectivesupport area for supporting the ribbon structures exhibiting high stressand/or tension.

In yet further embodiments of the invention, prior to cutting the devicelayer into ribbon structures, the device layer is coated or depositedwith a reflective top-layer. The reflective top-layer is preferablyformed from a reflective metal such as aluminum and can be deposited toa thickness in a range of 250 to 1000 Angstroms. Also while the anchorand post support features are preferably arranged in parallel rows alongthe ends of the ribbon structures, device configurations with staggeredsets of anchor and post support features are contemplated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 a-b are cross-sectional representations of a micro-structurecomprising a plurality of moveable ribbon structures, in accordance withthe embodiments.

FIGS. 2 a-b are cross-sectional representations of a micro-structurecomprising two sets of ribbon structures, in accordance with theembodiments.

FIG. 3 a is a cross-sectional representation of a ribbon structure, inaccordance with the embodiments.

FIG. 3 b is cross-sectional representation of a micro-structure having aplurality of ribbon structures, such as shown in FIG. 3 a.

FIG. 4 is a schematic block-diagram of a MEMS oscillator.

FIGS. 5 a-b show a top view and a cross-sectional representation of aMEMS on a chip, in accordance with the embodiments.

FIG. 6 a shows a schematic side view of a ribbon structure with anchorfeatures and a post support structure, wherein the separation betweenthe anchor support feature and the post support feature is modified, inaccordance with the method of the embodiments.

FIG. 6 b, shows a top view of a portion of a ribbon structure comprisinga support region with a single anchor support feature and single postsupport feature.

FIG. 6 c, schematically illustrates the effective support area providedby the support region shown in FIG. 6 b.

FIG. 7 a shows a top view of a micro-structure supported over asubstrate through a support region comprising a plurality of anchorsupport features and a plurality of post support features, in accordancewith a preferred embodiment of the invention.

FIG. 7 b schematically illustrates the effective support area providedby the support region shown in FIG. 7 a.

FIG. 7 c, shows a prospective view of a micro-structure supported over asubstrate through a support region comprising a plurality of anchorsupport feature and a plurality of post support features, in accordancewith the embodiments.

FIGS. 8 a-e, show forming support features, in accordance with themethod of the embodiments.

FIG. 9, shows a cross-sectional view of a micro-device with supportregions for supporting a ribbon structure near both ends of the ribbonstructure, in accordance with the embodiments.

FIG. 10 shows a schematic top view of a plurality of ribbon structuresarranged in parallel over a substrate each supported by a plurality ofanchor support features and a plurality of post support featuresarranged in parallel rows, in accordance with the embodiments.

FIG. 11 shows a schematic top view of a plurality of ribbon structuressupported through anchor support features and post support features in astaggered configuration, in accordance with an alternative embodiment ofthe embodiments.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring to FIG. 1 a, an optical MEM device can have a plurality ofmovable ribbons 100 that are spatially arranged over a substrate 102.The surfaces 104, corresponding to the ribbon tops and the regions ofthe substrate between the ribbons, are reflective. The surfaces 104 aremade to be reflective by depositing a thin film of reflective material,such as silver or aluminum on the substrate 102 and the ribbons 100. Theribbons and the substrate structure are micro-fabricated fromsilicon-based materials. The height difference 103 between thereflective surfaces 104 of the substrate 102 and the reflective surfaces104 of the ribbons 100 are configured to be λ/2 when the ribbons 100 arein the up position as shown in FIG. 1 a. When light having a wavelengthλ impinges on the compliment of reflective surfaces 104, light that isreflected from the surfaces 104 of the substrate 102 and ribbons 100will be in phase. Light which strikes the reflective surfaces 104 of thesubstrate 102 travels λ/2 further than the light striking the reflectivesurfaces 104 of the ribbons 100. Then the portion of light that isreflected back from the reflective surfaces 104 of the substrate 102returns traveling an addition λ/2 for a total of one complete wavelengthλ. Therefore, the compliment of the reflective surfaces 104 function asa mirror to the incident light source with a wavelength λ.

By applying an appropriate bias voltages across the ribbons 100 and thesubstrate 102, a portion of the ribbons 100 move towards and contact thesubstrate 102, as shown in FIG. 1 b. The thickness T^(r) of the ribbons100 is designed to be λ/4 plus the thickness of the reflective layer 104such that the distance 103′ is also λ/4. When light having a wavelengthλ impinges on surfaces 104 and 104′ with the ribbons 100 in the downposition, as shown in FIG. 1 b, the portion of light reflected from thesurfaces 104′ of the ribbons 100 will be out of phase with the portionof light reflected from the surfaces 104 of the substrate 102, therebygenerating the conditions for destructive interference. By alternatingthe ribbons between the positions for constructive interference, asshown in FIG. 1 a, and the positions for destructive interference, asshown in FIG. 1 b, the grating light valve is capable of modulating theintensity of reflected light from an impinging light source having awavelength λ.

FIGS. 2 a-b illustrate cross sectional views of an alternative opticalMEM device construction. In accordance with this construction, theoptical MEM device has a least two sets of alternating ribbons 206 and207 that are approximately in the same reflective plane. Referring toFIG. 2 a, the ribbons 206 and 207 are suspended over a substratestructure 202 by a distance 209. The ribbons 206 and 207 are providedwith a reflective surfaces 204 and 205, respectively. Preferably, thesurface of the substrate 202, or a portion thereof, also has areflective surface 208. The reflective surfaces of the substrate 208 andthe reflective surfaces of the ribbons 204 and 205 are preferablyconfigured to be separated by a distance approximately equal to amultiple of λ/2 of the impinging light source. Thus, the portion oflight that is reflected from the compliment of surfaces 204, 205 and 208are all phase, constructively interfere and the maximum intensity isobserved. In operation, the flat diffraction grating light valvealternates between the conditions for constructive and destructiveinterference by moving the first set of ribbons 206 or the second set ofribbons 207 relative to each other by a distance corresponding to λ/4.

In one mode of operation, light is modulated by moving one set ofalternating ribbons relative to a stationary set of alternating ribbons.The ribbons that are moved are referred to as the active ribbons and thestationary ribbons are referred to as the bias ribbons. The activeribbons are moved by any number of means including mechanical means, butare preferably moved by applying a sufficient bias voltage across theactive ribbon and the substrate to generate Coulombic attractionsbetween the active ribbons and the substrate.

Now referring to FIG. 2 b, when a sufficient bias voltage is appliedacross the active of ribbons 207 and the substrate 202, the ribbons 207are displaced relative to the bias ribbons 206 by a distance 203 that isapproximately equal to a multiple of λ/4. Accordingly, the portions oflight that are reflected from the surfaces 205′ of the active ribbons207 will destructively interfere with the portion of light that arereflected of the surfaces 204 of the bias ribbons 206. It will be clearto one skilled in the art that a grating light valve may be configuredto modulate an incident light source with a wavelength λ in otheroperative modes. For example, both sets of ribbons. 206 and 207 may beconfigured to move and separate by multiples of λ/4 in order toalternate between the conditions for constrictive and destructiveinterference. In addition, ribbons may or may not contact the substrateduring operation.

The ribbons of the MEM devices, described in FIGS. 1 a-b and FIGS. 2 a-bare preferably hermetically sealed within a die structure. Methods andmaterials used for providing a hermetically sealed die are described inthe U.S. patent application Ser. No. 09/124,710, filed Jul. 29, 2001,entitled “METHOD OF AND APPARATUS FOR SEALING AN HERMETIC LID TO A SEMICONDUCTOR DIE”, now U.S. Pat. No. 6,303,986, the contents of which arehereby incorporated by reference.

FIG. 3 a shows a cross-sectional view of a portion of a micro-structure300 formed in accordance with the embodiments. The micro-structure 300has a silicon based under-layer or support layer 305 that is preferablysilicon nitride-based with a thickness in a range of 700 to 1200Angstroms. The micro-structure 300 also has a reflective top-layer 301that is preferably formed from a metal and has thickness in a range of250 to 1000 Angstroms. The reflective top-layer 301 can be formed fromany number of metals and metal alloys, but is preferably formed fromaluminum or other metal that can be deposited using sputteringtechniques at relatively low temperatures.

Still referring to FIG. 3 a, the micro-structure 300 can also have asilicon dioxide layer 303 with a thickness in a range of 800 to 1800Angstroms. The silicon dioxide layer 303 is preferably interposedbetween reflective top-layer 301 and the under-layer 305. Alternatively,or in addition to the silicon dioxide layer 303, a silicon dioxide layercan be formed below the under-layer 305.

FIG. 3 b shows a portion of a micro-device 325, in accordance with theembodiments. The micro-device 325 preferably has a plurality of ribbonstructures 332 and 332′ geometrically suspended over a substrate 326.Each of the ribbon structures 332 and 332′ preferably has a multi-layerstructure comprising an under-layer 335, a top-layer 331 and ancompensating layer 333, such as those described above. The plurality ofribbons 332 and 332′ can comprise an alternating first set of ribbons332 and second set of ribbons 332′ which are moved relative to each,such as explained above. In accordance with the embodiments of theinvention, one set of the ribbons 332 or 332′ moves while the other setof ribbons remains stationary. In alternative embodiments, both set ofribbons 332 and 332′ move, although by different amounts, so that therelative phase of the light reflected from the ribbons 332 and 332′ canbe modulated from destructive through to constructive interference.

The substrate 326 can have a layer 325 of reflective material or anyother suitable material to assist in the functionality of themicro-device 325. Also, while the ribbon structures 332 and 332′, shownin FIG. 3 b, all have uniform widths W₁ and W₂ and spacings S₁, anynumber of ribbons constructions and arrangements with varied widths W₁and W₂ and varied spacings S₁ are contemplated. For example, ribbonstructure arrangements having varying widths W₁ and W₂ and optimizedspacings S₁ are described in U.S. patent application Ser. No.09/802,619, filed Mar. 8, 2001, entitled “HIGH CONTRAST GRATING LIGHTVALVE”, the contents of which is hereby incorporated by reference. Also,while the preferred micro-structure(s) comprise a silicon nitrideunder-layer, reflective metal top-layer and silicon dioxide layer(s), itis understood that the composition the nitride under-layer, a reflectivemetal top-layer and a silicon dioxide layer(s) can be varied withoutdeparting from the spirit and scope of the embodiments. For example, thereflective metal top-layer may be formed from an alloy and the siliconnitride and silicon oxide layers can contain impurities and/or dopantssuch a boron, phosphorus and the like.

Referring to FIG. 4, the embodiments can be included in MEMS. MEMS canhave any number or simple or complex configurations, but they alloperate on the basic principle of using the fundamental oscillationfrequency of the structure to provide a timing signal to a coupledcircuit. Referring to FIG. 4, a resonator structure 402 has a set ofmovable comb features 401 and 401′ that vibrate between a set of matchedtransducer combs 405 and 405′. The resonator structure 402, like apendulum, has a fundamental resonance frequency. The comb features 401and 401′ are secured to a ground plate 109 through anchor features 403and 403′. In operation, a dc-bias is applied between the resonator 402and a ground plate 409. An ac-excitation frequency is applied to thecomb transducers 405 and 405′ causing the movable comb features 401 and401′ to vibrate and generate a motional output current. The motionaloutput current is amplified by the current to-voltage amplifier 407 andfed back to the resonator structure 402. This positive feed-back loopdestabilizes the oscillator 400 and leads to sustained oscillations ofthe resonator structure 402. A second motional output current isgenerated to the connection 408, which is coupled to a circuit forreceiving a timing signal generated by the oscillator 400. In accordancewith the embodiments, anchor support features and post support featurescan be formed on the comb structures and or on the fingers of the combstructures to tune the MEMS oscillator to a preferred operatingfrequency.

FIG. 5 a shows a top view of a micro-device 550 in the plane of thearrows 571 and 573. The micro-device 550 comprises a chip 551 with oneor more comb structures 557 and 559. Each of the comb structures 557 and559 has a plurality movable ribbon micro-structures. One or more of thecomb structures 557 and 559 are preferably electrically coupled to acircuit 561, also on the chip 551 and configured for selectively movingthe ribbons of one or more of the comb structures 557 and 559.Preferably, the comb structures 557 and 559 are coupled to and/orsecured to the chip 551 through securing features 555 and 545. Thesecuring features 555 and 545 preferably comprise a plurality of anchorand post support features, such as those described in detail below. Themicro-device 550 also preferably has a sealing region around the combstructures 557 and 559 for sealing a optical lid, as described in detailabove.

FIG. 5 b illustrates a schematic side cross-sectional view of themicro-device 550 shown in FIG. 5 a, in the plane of the arrows 571 and572, which is orthogonal with the plane 571 and 573 through the line A-Aof the FIG. 5 a. From the side view shown in FIG. 5 b, it can be seenthat the comb structures 557 and 559 are suspended above the surface ofthe chip 551. The sealing region 590 can comprise a passivating layer582, as shown, to hold lid 575 above the suspended comb structure 557and 559. The lid 575 is preferably formed from glass, silicon, or othermaterial or combination of materials suitable for the application athand, viz. transparent to one or more wavelength of light to bemodulated.

Referring now to FIG. 6 a, a micro-structure configuration 600 comprisesa cantilever or ribbon structure 604. The structure 604 preferablycomprises a silicon nitride layer 607 and a reflective top-layer 605, asdescribed in detail above. The structure 604 is coupled to a suitablesubstrate (not shown) through a support region 603. The structure 604 ispreferably coupled to the substrate through one or more larger anchorsupport features 611 and one or more smaller post support features 613.The anchor support feature 611 and the post support feature 613 areseparated by a first distance D₁, which can be selected during thefabrication of the micro-structure configuration 600, such that thestructure 607 exhibits a preferred set of physical and/or mechanicalproperties, as explained in detail below. In accordance with theembodiments, the larger anchor feature 611 preferably has averagecross-sectional width W_(a) in a range of 5.0 to 20 microns and the postsupport structure 613 preferably has an average cross-sectional widthW_(p) in a range of 0.5 to 5.0 microns. However, it is understood thatactual dimensions of the anchor and post support features chosen willdepend on the dimensions of the structure 604.

In accordance with the method of the embodiments, the physical ormechanical properties of the structure 604 can be tuned during thefabrication micro-structure configuration 600 by selecting theseparation of the anchor support feature 611 and the post supportfeature 613 or by providing an additional post support feature 613′ asshown by the dotted line, such that the anchor support features 611 andthe second post support feature 613′ are separated by a second distanceD₂. Accordingly, the structure 604 is supported through a larger supportregion 603′ and will generally require more energy to deflect or movethe active portion 608 of the structure 604.

FIG. 6 b shows a top view of the micro-structure 604 comprising a singleanchor support features 611 and a single post support features 613. Theeffective support surface area provided by a support region 603comprising one anchor support feature 611 and one post support feature613, illustrated schematically in FIG. 6 c. Note that the effectivesupport surface area is related to W_(s) and L_(s). For larger ribbonstructures, which are supported from both ends and which are under highstress and/or tension, sufficient structural support may not be providedthrough support regions having only one anchor support feature and onepost support feature.

Now referring to FIG. 7 a, a micro-structure 704 in accordance with theembodiments is preferably supported through one or more support regions703 comprising a plurality of anchor support features 711 and 711′ and aplurality of post support features 713 and 713′. By implementingmultiple anchor support features and multiple post features within eachof the support regions, the effective support area in each supportregion 703, related to L_(s2) and W_(s2), can be increased asillustrated schematically in FIG. 7 b. Accordingly, support regions,such as 703, have the potential to support micro-structure exhibitinghigher stress and/or tension.

FIG. 7 c shows a portion of a suspended micro-structure 707, that issupported over a suitable substrate 701 through the support region 703comprising a plurality of anchor support features 711 and 711′ and aplurality of post support features 713 and 713′, such as describedabove. The micro-structure 707 is preferably a ribbon structure that isalso supported by a second support region also having a plurality ofanchor support features and a plurality of post support featurespositioned at an opposing end of the 707.

In accordance with the method the embodiments, anchor and posts supportfeatures are formed by similar processes. FIGS. 8 a-e will be used toillustrate the formation of an anchor support feature or a post supportfeature. Referring to FIG. 8 a, a layer 801 of sacrificial material,such as poly-silicon, is deposited onto a suitable substrate structure802, which preferably comprises an oxide layer, as explained in detailbelow. The sacrificial layer 801 is etched to form a patternedsacrificial layer 801′ that is patterned with a support trench or asupport dimple 804 as shown in FIG. 8 b. The sacrificial layer 801 ispreferably etched such that a portion of the substrate surface 805 isexposed and, thereby, is available for coupling with a device layer 803,as described in detail below.

After the support trench or dimple 804 is formed, then the device layer803 is formed over the patterned sacrificial layer 801′ such that aportion of the device layer 803 is formed over the exposed surface ofthe substrate 805 and through the support trench or dimple 804, therebyforming a support features. The device layer 803 preferably comprisessilicon nitride and can also comprise one or more layers of siliconoxide and/or a reflective top layer, as described in detail below.

Now referring to FIG. 8 d, after the device layer 803 is formed, thenthe patterned sacrificial layer 801′ is etched, or partially etched, toform voids or gaps 801″ and release the device layer 803, which remainscoupled to the substrate 802 through the support feature formed in thesupport trench 804. Preferably, the patterned sacrificial layer 801′ isetched using a dry etch process, such as described in the U.S. patentapplication Ser. No. 09/952,626, entitled MICRO-ELECTRONIC MECHANICALSYSTEM AND METHODS, filed Sep. 13, 2001, the contents of which is herebyincorporated by reference. In a preferred method of the invention thedevice layer 803 is cut or divided into ribbon structures prior toetching the patterned sacrificial layer 801′, whereby each of thereleased ribbon structures remain coupled to the substrate 802 throughsupport regions comprising a plurality of anchor support features and aplurality of post support features. FIG. 8 e shows a perspective view ofan anchor or a post feature 811 coupled to the substrate 802 andsupporting the released device layer 803 formed in accordance with themethod described above.

FIG. 9 illustrates a cross-sectional representation of a micro-devicecomprising a multi-layer ribbon structure 908, in accordance with apreferred construction. The micro-device comprises a substrate 902,which can comprises a wafer layer 901, and silicon oxide layers 903 and907, with a poly-silicon layer 905 therebetween. The thicknesses of thelayers 901, 903, 905, and 907 are varied depending of the application athand. However, it is preferable that the oxide layer 907 is present tocouple to a ribbon structure 908, as previously described. The ribbonstructure 908 preferably comprises a layer of silicon nitride 911, and alayer reflective top layer 915 of aluminum, as previously described. Insome applications, a layer of silicon oxide 913, with a layer thicknessin a range of 500 to 2000 Angstrom, can be provided to reduce strainbetween the silicon nitride layer 911 and the reflective top layer 915.

Still referring to FIG. 9, the ribbon structure 908 is preferablysuspended over the substrate structure 902, such that there is one ormore gaps 909 between the ribbon structure 908 and the substratestructure 902. Preferably, the ribbon structure 908 is supported to orcouples to the substrate structure 902 through anchor support features920 and 995 and post support features 923 and 927, as previouslydescribed, wherein a plurality of anchor support features and aplurality of post support features support each end of the ribbonstructure 908.

Referring now to FIG. 10, a MEM device 950 in accordance with theembodiments has a plurality of ribbon structures 969, 971, 973, 975 and977 supported over a suitable substrate structure 951 through both endsof each of the ribbons 969, 971, 973, 975 and 977. The ribbons 969, 971,973, 975 and 977 are arranged in parallel and separated by a distance S₃in a range of 0.2 to 2.0 microns. The ribbon structures 969, 971, 973,975 and 977 are preferably in a range of 50 to 500 microns long L₃ andin a range 4.0 to 40 microns wide W₃. A supporting region 953 preferablycomprises a plurality of anchor support features 961 and a plurality ofpost support features 903 and 965, which are arranged in parallel rowsalong adjacent ends of each of the ribbon structures 969, 971, 973, 975and 977. In accordance with an alternative embodiment, a MEM device canhave sets of ribbons with anchor support features and post supportfeatures having varying or alternating separations, such a shown in FIG.11.

Now referring to FIG. 11, in accordance an alternative embodiment,micro-device 150 has a first set of ribbon structures 180 with a firstset of anchor support features 161 and post support features 163. Thefirst set of anchor support features 161 and post support features 163are separated by a distance D₄ to provide a first set of active regions55. A second set of ribbon structures 190 have a second set of anchorsupport features 171 and post support features 173. The second set ofanchor support features 171 and post support features 173 are separatedby a different distance D₅ to provide the second set of active regions56. The active regions 55 and 56 will have different mechanical andphysical properties and, therefore, will operate at a differentfrequencies or will be actuated by different switching voltages. FIG. 11is used for illustrative purposes only and any number of variations areconsidered to be within the scope of the embodiments. Also, while thefirst set of ribbon structures 180 and the second set of ribbonstructures 190 are schematically illustrated as having a single anchorand post support feature at each end, it is understood that each ribbonwithin the set of ribbons 180 and 190 are preferably coupled throughsupporting regions comprising a plurality of anchor support features anda plurality of post support features, as described in detail above.

The present invention provides for a MEM device and/or an optical MEMdevice which can be tuned during fabrication by selecting theseparations between anchor support structures and post supportstructures. Preferably, the MEM device of the embodiments has pluralityof movable micro structures each supported through a plurality of anchorsupport features and a plurality of post support features. Morepreferably the MEM device of the embodiments has a plurality of ribbonstructures each supported through opposing ends by a plurality of anchorsupport structures and a plurality of post support features.

The present invention has been described in terms of specificembodiments incorporating details to facilitate the understanding of theprinciples of construction and operation of the invention. While thepreferred micro-device of the embodiments is an optical MEMS device, theinvention in contemplated to be useful for making any number ofmicro-structure and micro-structure devices including cantileverdevices. As such, references, herein, to specific embodiments anddetails thereof are not intended to limit the scope of the claimsappended hereto. It will be apparent to those skilled in the art thatmodifications can be made in the embodiment chosen for illustrationwithout departing from the spirit and scope of the invention.

1-9. (canceled)
 10. A micro-structure comprising an elongated ribboncoupled to a substrate though at least two securing regions, eachsecuring region comprising a plurality of larger anchor featuresarranged in a row along a width of the elongated ribbon and a pluralityof smaller anchor features arranged in a parallel row along the width ofthe ribbon.
 11. The micro-structure of claim 10, wherein a portion ofthe elongated ribbon is configured to move up and down relative to thesubstrate structure, and wherein the elongated ribbon comprises siliconnitride with a reflective top-layer.
 12. (canceled)
 13. Themicro-structure of claim 10, wherein the at least two securing regionsare arranged near the ends of the ribbon.
 14. A method of making amicro-device comprising: a. forming rows of support regions in asacrificial layer, the support regions comprising posterior anchorfeatures and interior post features, the posterior anchor features andinterior post features being separated by a distance; b. formingparallel ribbon structures over the rows of support regions andextending between the rows of support regions; and c. removing at leasta portion of the sacrificial layer between the rows of support regionsand under the ribbon structures to form suspended ribbon structures. 15.The method of claim 14, wherein the suspended ribbon structures areunder tensions of 1.5 Gpa or more.
 16. The method of claim 14, whereinthe ribbon features each span a plurality of posterior anchor featuresand interior post features from each of the rows of support regions. 17.The method of claim 14, wherein the step of forming the support regionscomprises etching the sacrificial layer through one or more masks. 18.The method of claim 14, wherein the suspended ribbon structures are in arange of 50 to 1000 microns long, and wherein the suspended ribbonstructures are in a range of 4.0 to 40 microns wide.
 19. (canceled) 20.The method of claim 14, wherein the step of forming the ribbon featurescomprises depositing a continuous device layer with a thickness in arange of 500 to 2,000 Angstroms over the sacrificial layer.
 21. Themethod of claim 20, wherein the continuous device layer is a siliconnitride layer.
 22. A device comprising a plurality of ribbons suspendedover a substrate, wherein each of the ribbons are suspended over thesubstrate by opposing ends through a plurality of anchor features and aplurality of post features.
 23. The device of claim 22, wherein theribbons are in a range of 4.0 to 40 microns wide and 50 and 1000 micronslong, and wherein the ribbons comprise layers of silicon nitride thatare in a range of 500 to 2000 Angstroms thick and a top-layer ofaluminum with a thickness in a range of 250 to 1500 Angstroms thick. 24.(canceled)
 25. (canceled)
 26. The device of claim 22, wherein at least aportion of the ribbons are configured to move relative to the substrateto modulate a light source having a wavelength in a range of 300 to 3000nanometers.
 27. A method of fabricating an optical MEM devicecomprising: a. depositing a layer of poly-silicon on a suitablesubstrate; b. etching the poly-silicon with a first set of anchor andpost dimples; c. depositing a device layer over the poly-silicon layerand the dimples to form a first set of anchor and post features whichare coupled to the substrate; d. dividing the device layer into ribbonssuch that two or more anchor and post features from the first set ofanchor and post features are coupled to each of the ends of the ribbons;and e. etching the poly-silicon layer to release the ribbons.
 28. Themethod of claim 27, wherein the substrate comprises a layer of siliconoxide, wherein the device layer comprises silicon nitride, and whereinthe step of dividing the device layer into ribbons comprises cutting thedevice layer into the ribbons using a reactive ion etch process. 29.(canceled)
 30. The method of claim 27, wherein the anchor features havecross-sectional dimensions in a range of 5.0 to 20 microns and the postfeatures have cross-sectional dimensions in a range of 0.5 to 5.0microns.
 31. (canceled)
 32. The method of claim 27, wherein the firstset of anchor and post features are in parallel rows.
 33. The method ofclaim 27, wherein the anchor features of the first set of anchor andpost features are in row and the post features are staggered.
 34. Themethod of claim 27, further comprising etching the poly-silicon with asecond set of anchor and post dimples before depositing the device layerand depositing the device layer over both of the first set and thesecond set of anchor and post dimples to form a first and second set ofanchor and post features and wherein the device layer is divided intoribbons such that two or more anchor and post features from both of thefirst set and the second set are coupled to each of the ribbons.
 35. Themethod of claim 34, wherein the first set of anchor and post featuresand the second set of anchor and post features are coupled to each ofthe ribbons at opposite ends of the ribbons.